Somatic genes required for post-meiotic spermatogenesis

描述(申请人提供)：由于精子发生的机制在所有动物门中都是保守的，对人类男性不育原因的见解可能来自对模型生物的研究。在果蝇减数分裂后精子发生过程中，单倍体精子细胞核的胞囊成熟为一束有组织的成熟精子。这一成熟过程包括核的形成和延长、轴丝的构建和精子细胞的个体化，其中每个细长的精子细胞被包裹在自己的质膜中，发生在由两个体细胞囊细胞组成的生精囊内。虽然这两个囊细胞在早期精子发生中发挥了关键的信号作用，但它们在减数分裂后精子发生中的作用尚不清楚。这项工作旨在揭示精子减数分裂后成熟所需的体细胞囊泡细胞中的基因。使用P-元件增强子-检测器线和GFP标记的蛋白质陷阱，将分离在精子发生后期在囊细胞中表达的基因。随后，通过从候选插入中分离相邻的基因单位来发现相应的基因，并获得突变。在一种互补的方法中，适当表达的基因将通过P元件动员产生新的突变。新获得的突变体将使用光学显微镜筛选晚期生精缺陷。表型有趣的突变将使用已知的分子标记和荧光显微镜进一步表征。将对减数分裂后精子发生的候选体细胞调控因子进行测序，并将在其他物种中鉴定相关基因。由于昆虫和哺乳动物的精子发生在功能上是相似的，识别果蝇精子细胞成熟的体细胞调控因子可能有助于揭示哺乳动物睾丸中体细胞支持细胞和生殖系之间的相互作用，从而为深入了解哺乳动物精子细胞形态发生的体细胞调控，最终了解人类男性生育的机制提供帮助。

DESCRIPTION (provided by applicant): Since the mechanisms of spermatogenesis are conserved across all animal phyla, insights into the causes of human male infertility may come from studies in model organisms. During post-meiotic spermatogenesis in Drosophila, a cyst of 64 haploid spermatid nuclei is matured into an organized bundle of 64 mature spermatozoa. This maturation process, which includes nuclear shaping and elongation, construction of the axoneme, and spermatid individualization, in which each elongated spermatid is invested within its own plasma membrane, occurs within a spermatogenic cyst comprised of two somatic cyst cells. While these two cyst cells have been shown to play critical signaling roles during early spermatogenesis, their roles during post-meiotic spermatogenesis remain uncharacterized. This work seeks to uncover genes required in the somatic cyst cells for the post-meiotic maturation of spermatozoa. Using both P-element enhancer-detector lines and GFP-tagged protein traps, genes expressed in the cyst cells during late-stage spermatogenesis will be isolated. Subsequently, the corresponding genes will be uncovered by isolating neighboring genetic units from candidate insertions and mutations will be obtained. In a complimentary approach, novel mutations in appropriately expressed genes will be generated by P-element mobilization. Newly obtained mutants will be screened for late-stage spermatogenic defects using light microscopy. Phenotypically interesting mutations will be further characterized using known molecular markers and epi-flourescence microscopy. Candidate somatic regulators of post-meiotic spermatogenesis will be sequenced and related genes will be identified in other species. Since insect and mammalian spermatogenesis are functionally similar, identification of somatic regulators of spermatid maturation in Drosophila may help uncover interactions between the somatic Sertoli cells and the germline in the mammalian testis, thus providing insight into somatic regulation of mammalian spermatid morphogenesis, and ultimately, into the mechanisms governing human male fertility.